Structural studies of the bacterial ribosome have been limited either to low resolution cryo-electron microscopy and x-ray diffraction studies of whole ribosomes, or to high resolution x-ray and NMR studies of individual ribosomal proteins. We have successfully co-crystallized the ribosomal protein S15 from Bacillus stearothermophilus with its ribosomal RNA binding site. These crystals, however, do not grow much larger than 0.6 x 0.2 x 0.2 mm and diffract weakly to 3.5 E in house under cryo conditions. This work requires synchrotron radiation to collect data on native crystals to the highest possible resolution and to collect data on potential isomorphous heavy atom derivative crystals.